Window frame material /

What choice of materials is available?

When modernising an existing building or even when building a new one, the question quickly arises about which windows to fit. At the same time, the question isn't necessarily about the windows' shape or design, because straight away it's a question of the material. In Germany, window frames are usually made from three materials: Timber, PVC and aluminium. At present, another product – mixed windows made of timber and aluminium – is not yet used as frequently. Each material has both advantages and disadvantages. Here we would like to explain to you the different materials, and also give you some guidelines to hopefully help you make your decision.

The window market in Germany based on frame materials, in window units from 2000 – 2014

Timber frame /

The original window type

Timber has been a commonly used frame material ever since windows with glass panes have been fitted in homes. Timber window frames have a very natural appearance, in addition to which timber possesses excellent insulating properties that stand out in a positive way in residential buildings in particular. Timber window frames are primarily made from spruce, pine and oak. The three types of timber are regarded as robust, and are renewable raw materials. This makes timber windows very environmentally friendly. It is also a material that can help to balance out CO2 levels. However, timber windows are not without their disadvantages. For one thing, their durability is limited. The timber decomposes under the influence of the weather, taking on an unattractive appearance over time. Timber window frames must also be coated regularly with special varnishes or paints in order to improve their durability. Another problem with timber window frames is that timber is a "working" natural product. Temperature changes can cause expansion and shrinkage, in some cases resulting in the frames not sitting securely in the façade if they have not been properly fitted. The durability of timber window frames depends on the care they receive, the type of timber and the weathering that the windows are subjected to. The prices of timber windows are also dependent on the type of timber. Generally speaking, frames made of hardwood are more expensive than those made of coniferous wood. The size and type of the glazing also determine window prices.

For timber window frames, the overall balance of advantages and disadvantages is as follows:

+ natural appearance
+ renewable raw material
- requires a lot of care
- regular painting required
- can swell
- not very durable if not looked after properly
- relatively high price

PVC frames /

Very robust and easy to maintain, with an individual appearance

Since the emergence of PVC window frames, they have succeeded in displacing timber windows in many places. There are many factors in favour of choosing PVC frames. Window prices are within a very reasonable range and these windows are very durable.

The window frames are made of high-quality PVC that has a significant influence on their durability. PVC windows can also be optimally combined with security measures. Another advantage of this window type is that it can be manufactured in almost any shape and size. PVC window frames are relatively light and are suitable even for large window fronts.

However, the great advantage is that PVC window profiles score better than aluminium or timber frames in terms of insulation values, thereby reducing energy and heating costs. Special foils also allow PVC window frames to be designed in many colours, which means that they blend in perfectly with the house façade. Nevertheless, a PVC window also has its disadvantages. Unlike timber windows, the synthetic material does not improve the living environment. On very light frames, dirt can be deposited very visibly on the PVC, resulting in a less attractive appearance. However, PVC frames are regarded as being extremely easy to look after because they require no special protection and do not require painting or varnishing. The overall summary is as follows:

+ very durable – last for up to 50 years
+ low maintenance
+ very good insulation properties
+ many different shapes are possible
+ frames available in various colours
+ light weight
+ easy to clean
+ low price
+ 100 % recyclable and therefore particularly resource-friendly.
- light frames get dirty easily
- not a natural raw material

Take a look at our PVC windows overview.

Aluminium frames /

The uncommon choice

Aluminium is another option for window frames. These windows come with a very high price tag however, which means that they are used relatively rarely in the construction of homes. One stand-out advantage of this material is its long durability. Aluminium is weather-resistant and does not rust. However, it is a material that can cool down and heat up a lot, which significantly reduces its insulating properties. Aluminium frames are very popular for large, modern window fronts. The light weight of the material is a factor here. Caring for aluminium frames is limited to cleaning with water and the usual cleaning agents. The overall balance is as follows:

+ durability for many years
+ requires little in terms of care
+ a modern look
+ streamlined appearances are possible
+ almost all colours are possible
- high window costs
- comparatively poor insulating properties
- risk of corrosion, e.g. in the case of buildings near the sea

Aluminium claddings – a combination of more than one material

Timber and PVC windows can be combined with aluminium claddings that are clipped onto the outside of the window frame. This gives you the classic appearance of an aluminium window, but with the better insulation values of timber or PVC. The window frame is also protected against the influences of the weather, thereby making it easier to look after – particularly in the case of timber frames. Another advantage is that almost all colours are possible – entirely to your taste!

We supply aluminium claddings for the Prestige and Eforte systems.

More details about this can be found here.

Which window should I choose?

Of course, which window frames should ultimately enhance a new home depends on the home-owner's personal preferences. However, the popularity of PVC frames already tips the balance towards choosing this product. The fact that they require little in terms of looking after, the relatively low window prices and the possibility of adapting the window frames explicitly to your own requirements deliver significant advantages. Frame foils also allow the PVC to be given the look of natural timber windows. The environmental aspect also certainly plays an important role. Whereas natural raw materials have to be used for timber and aluminium windows, PVC windows are completely synthetic. However, the material used is 100% recyclable and is completely reused after the windows are replaced. Normally, the material can be reprocessed up to ten times.

However, it is of course entirely the home owner's decision as to which window frames should be used. An extensive comparison of windows enables the positive properties and effects of the individual windows to be compared against each other very well. Before making a final decision, it is recommended to look at the various frame types in situ, to gather sufficient information and to make a window price comparison.


Taking the long view

Of course, it is understandable that attention will be paid to the price of windows when choosing a new window frame. Nevertheless, it should always be borne in mind that investing in high-quality and durable windows represents a long-term acquisition. Energy costs will be sustainably reduced if the window frames have a good insulation value, and if they are even fitted with triple glazing. High-quality materials also ensure that the windows will not need to be replaced for many years. Ultimately, these points too should be borne in mind when comparing windows, and should also be included in the window price comparison. Practical experience has shown that investing in high-quality and durable window frames brings with it more savings potential than choosing lower-quality windows.